The 32-year-old forward recently admitted he was keen to work under the Portuguese once again, while the Chelsea boss has refused to rule out a move for the Cameroon international
Reports have suggested the big-spending Russian side is looking to cut costs, with the 32-year-old forward among the players who could be offloaded this summer.
Eto'o claimed he would relish the chance to work with Mourinho once again after winning the Champions League and Serie A under the Portuguese at Inter, while the Chelsea manager refused to rule out a move for the Cameroon international.
"I am always happy that somebody that worked with me previously is happy to be back and work with me again," Mourinho told BT Sport. "That is a good feeling that I have, when I read something that Samuel is keen.
"It is fantastic for us, but we are going to see what happens."